What are the features that really set apart the brushless motors in the 15-20kw range such as the Hacker A200, Predator 37, Joby Motors, etc. Is it the Kv that makes a large difference? The Predator has a unique design that allows better cooling from spaces in the center of it, other than that I don't have enough understanding of these high watt brushless motors to really discern them from eachother.

Motor quality depends on the grade of magnets, wire, bearings and its ability to dissipate heat. The wattage that the manufacture places on the label may be over rated or under rated by independent testing. The KV is the RPM for every volt your battery pack puts out. A 110 Kv motor at 48v will spin the shaft at 5,280 RPM. The Kv of your motor matched with your battery pack output volts along with your gear ratio may help govern your design for let’s say a flat environment or a hilly environment.